Hashtable stores data as Key Value pairs. It is very efficient when you have lot of data and need to search for keys.
Following sample shows how to add Key/Value pairs to the Hashtable.
Hashtable table = new Hashtable();
table.Add("John", "2003");
table.Add("Tom", "1975");
table.Add("Teena", "1988");
You can retrieve the value from hashtable using the indexer.
string val = table["John"].ToString();